IMP非常慢的问题

最近有同事碰到IMP非常慢的问题，其间查到一篇METALINK文档305211.1，这里记载一下：

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Symptoms

Import is slow on Particular Table.

- Process state dump shows imp is waiting for 'log file sync'

application name: imp (TNS V1-V3), hash value=0
waiting for 'log file sync' blocking sess=0x0 seq=4338 wait_time=0

- If you import with Commit=N its quick

- From 10046 event we always see waiting statement

INSERT /*+NESTED_TABLE_SET_REFS+*/ INTO

Cause

For a number of data types, imp will insert one row at a time.

This is expected behavior. If table has following datatypes ,

LOBs, LONGs, ADTs (user-defined types), ROWID/UROWIDs and the timestamp.

Solution

This issue is same as Bug 2797580IMP WITH TIMESTAMP COLUMN REQUIRES MUCH MORE TIME OVER TABLE WITHOUT TIMESTAMP,

which is closed as not a bug and
subsequently an enhancement request was logged

Workaround for this issue is to use Commit=N parameter while import.

来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/85922/viewspace-1026835/，如需转载，请注明出处，否则将追究法律责任。

转载于:http://blog.itpub.net/85922/viewspace-1026835/